The present invention relates to blow-molded bottles, typically made of a plastic such as polyethylene terephthalate (PET), useful in containing beverages that are hot-filled into the bottles. The present invention relates particularly to a structure for a surface portion, particularly the shoulder portion, of such bottles useful to at least partially compensate for any post capping vacuum within the bottle.
Plastic blow molded bottles intended to be hot-filled have previously been provided with a variety of features intended to at least partially compensate for the post-capping development of a partial vacuum within the bottle upon cooling of the contents. For example, U.S. Pat. Nos. 5,005,716; 5,503,283; 6,595,380; 6,896,147; 6,942,116; and 7,017,763 disclose blow molded bottles that can be used in hot-fill operations, which include features in the base of the bottle intended to at least partially compensate for the post capping development upon cooling of a partial vacuum. U.S. Pat. Nos. 5,092,475; 5,141,121; 5,178,289; 5,303,834; 5,704,504; 6,398,052; 6,585,125; 6,698,606; and 7,032,770 disclose blow molded bottles that can be used in hot-fill operations, which include features in the side wall of the bottle intended to at least partially compensate for the post capping development of a partial vacuum. U.S. Pat. Nos. 5,222,615; 5,762,221; 6,044,996; 6,662,961; and 6,830,158 disclose blow molded bottles that can be used in hot-fill operations, which include features in the shoulder of the bottle intended to at least partially compensate for the post capping development upon cooling of a partial vacuum.
U.S. Pat. Nos. 5,392,937; 5,407,086; 5,598,941; 5,971,184; 6,554,146; and 6,796,450 disclose blow molded bottles that can be used in hot-fill operations, which include axially rotationally symmetric shoulders between a side wall and a neck of each bottle. The shoulders of these bottles have a circumferentially continuous outwardly extending upper margin adjoining the neck, an outwardly protruding ring immediately above the side wall, and a concave perimeter surface joining the upper margin to the outwardly protruding ring. This shoulder structure is sometimes described as one that is convenient for grasping the bottle, and has been recognized in U.S. Pat. No. 6,016,932 as possibly contributing to poor top load capabilities. There is not been any recognition that such a substantially axially rotationally symmetric concave perimeter surface could be useful in at least partially compensating for the post capping partial vacuum within the bottle.
Despite the various features and benefits of the structures of the forgoing disclosures, there remains a need for alternative geometries for bottle that can be hot filled and have a substantially axially rotationally symmetric geometry that can accommodate the post capping development of a partial vacuum within the bottle. There further remains a need for such a bottle having a substantially axially rotationally symmetric geometry that effectively resists ovalization of the sidewall. There is a further need for such a bottle that will uniformly conform to a specified geometry following hot filling so that the bottles will have a uniform appearance at the time of customer selection and purchase.